Uintas Avalanche Advisory Sunday, December 28, 2008 Created at 5:55 am Updated at 6:19 am Forecaster: Craig Gordon SPECIAL ANNOUNCEMENT A SPECIAL AVALANCHE ADVISORY remains in effect for the western Uinta Mountains. A HIGH avalanche danger exists on all steep mid and upper elevation slopes. Human triggered avalanches are certain, natural avalanches are possible. Backcountry travel is not recommended. BOTTOM LINE Danger by aspect and elevation on slopes approaching 35° or steeper. At and above treeline the avalanche danger remains HIGH today with severe consequences on all slopes approaching 30 degrees in steepness, especially those with recent deposits of wind drifted snow. Human triggered avalanches are likely. Today’s avalanches will break into weak layers of snow near the ground, creating a large, dangerous and possibly unsurvivable slide. At mid elevations the avalanche danger is CONSIDERABLE on steep wind drifted slopes and human triggered avalanches are probable. Remember- even if you're traveling on relatively flat terrain, be aware of steep slopes above and adjacent to you and avoid avalanche runout zones. CURRENT CONDITIONS Skies are mostly cloudy and there’s a lingering flurry or two as the region remains under the influence of a moist westerly flow. Winds have backed off significantly overnight and are generally blowing out of the west averaging 5-15 mph at most locations, gusting into the 20’s and 30’s along the high ridges. An inch of snow fell in the past 24 hours, bumping upper elevation total snow depths to just about 50”. RECENT ACTIVITY Tuesday’s unfortunate avalanche accident in the Logan Mountains resulted in the death of two local snowmobilers. My thoughts and prayers go out to friends and family of these two young men. Closer to home, the region is experiencing an active avalanche cycle which started last Sunday. Very large natural avalanches along with snowcat, remotely triggered, intentionally human triggered and explosives triggered (photo one, photo two) avalanches have been reported. Averaging 3’-4’ deep, all the slides are breaking on or just below the Thanksgiving rain crust near the ground and are up to 400’ wide. In addition, avalanches are breaking out along ridgelines in relatively flat terrain. Also, Joe Donnell from the State Parks grooming crew triggered numerous slides yesterday on the Wolf Creek/Soapstone Road. Any one of these benign looking slopes could easily bury a person. Thanks everyone for all the awesome observations this week! I especially want to thank Ted Scroggin, Joe Donnell and the staff at Park City Powder Cats for their professional dialog, advice and insight during this challenging avalanche cycle. THREAT #1 Impressive snow and water totals from the Christmas storm left our weak snowpack reeling. Persistent buried weaknesses need time to adjust and we’ll have to exercise patience as the pack begins to heal. The goods news is the region experienced a widespread natural avalanche cycle and some of our worries have been flushed away. The bad news is most of the evidence is covered over with new snow making it hard to detect exactly which slopes have avalanched. Many steep slopes hang in the balance waiting for a trigger to come along and knock the legs out from under our structurally challenged snowpack. Not much has changed the past few days and it remains spooky out there. The natural avalanche cycle is beginning to wane and this is the time stability patterns become a little less predictable. As the snowpack starts to gain strength avalanches may be harder to trigger, but unfortunately the ones you do initiate are bigger, wider and deeper. Avalanches triggered today will be large, dangerous and most certainly unsurvivable. They can be triggered from a distance and on relatively flat terrain. In addition, avalanches are being triggered from ridgelines and over running islands of safety. All the signs of instability are around us and we’ll just need to chill out, tone our slope angles down and have some patience as the snowpack adjusts. Right now, meadows and groomed trails are the ticket. Remember- even if you’re playing in flat terrain think about steep slopes above and adjacent to you and avoid avalanche runout zones. THREAT #2 West and northwest winds were ruthless yesterday, gusting into the 50’s and 60’s along the upper elevation ridges. As a matter of fact they’ve been strong all week, creating deep wind slabs along the leeward side of ridges and around terrain features like chutes and gullies at both mid and upper elevations. Wind slabs remain sensitive to the weight of a rider today. Once triggered, these fairly manageably sized slabs can quickly get out of hand initiating a much larger, wider and more dangerous avalanche than you bargained for. MOUNTAIN WEATHER A westerly flow persists over the region today producing mostly cloudy skies and a scattered snow shower or two. Temperatures will be slightly warmer with highs today reaching into the upper 20’s at 8,000’ and near 22 degrees at 10,000’. Overnight lows dip into the mid teens. Westerly winds should remain fairly well behaved, blowing 5-15 mph with gusts in the low 30’s along the peaks. Winds switch to the southwest later tonight, becoming slightly stronger, gusting to 35 mph at the upper elevations. A storm clips the northern half of the state Monday night and it looks like quiet weather is on tap for the New Year.